Steps Must Almost Always Be Taken to Evaluate Missing Data

Steps must almost always be taken to evaluate missing data problems. What occurs with a missing completely at random values pattern?

A) Missing values are just a random sample of all cases in the population.
B) Missing values are just a random subsample of all cases in the sample.
C) Missingness is related to other variable sbut not related to the value of the variable that has the missing values.
D) A pattern in which the value of the variable is missing is related to its missingness.